blender 2.8 First bake failed
In the Shader editor create a new blank image in the low poly anvil's material and set its panel active (select it and its white outline must be appear). Select the high poly anvil then the low poly (so the hp must be orange, the lp must be yellow) and click on bake in the render properties panel. You have to increase the ray distance a little before the baking (probably mine wasn't the optimal).